This project is directed at continued development, support and applications of a multiple function video microscope system which incorporates state-of-the-art digitally controlled video cameras, computer image acquisition, processing and storage, ultra-low light capability, and the ability to perform spatially and temporally resolved experiments on microscopic biological samples. The system has been designed for quantitative measurements of fluorescent and self-luminescent samples. In conjunction with cell injection techniques using the bioluminescent calcium indicator protein, aequorin, and a variety of fluorescent probes of cellular function, this system is being used to investigate a variety of stimulus/response effects including those which are mediated via calcium ions and/or calmodulin; phototropic effects mediated via phytochrome and blue light photoreceptors; insulin responses in adipose cells; and the regulation and control of bioluminescence at the cellular level. The combined facilities of this project are being used to probe the biochemical events in stimulus, response coupling in intact, living cells. Specific aims during this project period are continued developments of hardware and software for quantitative analysis of vidic microscopic images, improvements in microinjection and the use of chemically specific probes of cellular biochemistry, and continued collaborative studies of a variety of stimulus/response effects.